Suspension design..........

[Matt Pascoe]

By too moch artuclation; do you mean that you need bumpstops to avoid stuffing your tires into the flares?

No, plenty of room to stuff (I trimmed ALOT). If the drooped side drops much more than in the above pic, the rear steer forces the inside rear of the compressed tire into the frame.

I definately need a center strap. My drive shaft ujoints will bind long before the axle stops dropping

Using your logic, the headlights on your rig are oval.

Please dont confuse genius with logic

I decided to be a trend setter and swap the far superior YJ front clip onto a TJ

JK

[DsrtJeeper]

I wheel with a friend that has a YJ converted to TBT's rear suspension. His rig works extremely well! Maybe it's a good thing to have more travel in the rear than the front?

[John]

Originally posted by Matt Pascoe

I definately need a center strap. My drive shaft ujoints will bind long before the axle stops dropping

Swap to a shaft using Toyota CV and joints. They're got WAY more working angle then the 1310 stuff.

[DsrtJeeper]

Originally posted by John
Swap to a shaft using Toyota CV and joints. They're got WAY more working angle then the 1310 stuff.

Very interesting..... Got pics?

By the way; I run a 1310 into 1330 cv combo for a high angle shaft. I'm not sure a full 1310 cv setup will work for anything much over a 4" lift.

[John]

Sorry no pics. And I just gave away the last Toyota shaft I had laying around last night.

IIRC it's a difference of 40-41? for the Toy stuff vs. 28? for the 1310 though

[DsrtJeeper]

Quite a difference! You could also buy offset trunion u-joints from Tom Woods.

[mrblaine]

Originally posted by DsrtJeeper
Quite a difference! You could also buy offset trunion u-joints from Tom Woods.

The only place they would help is in the CV and they won't work there according to TW.

[Matt Pascoe]

I just crawled under the Jeep with an angle finder, and sitting leval my t-case point down at 6* and my 1310CV shaft is at 24*. So I'm at 18* operating angle at rest.

Tom Woods' site says he can get 30-35* out of a 1310 CV with a little tweeking. I'll have to see how it looks drooped

I do know that I bound my CV at TDS. I can see where the CV center housing contacted the u-joint cap.

Oh, and Rick pointed out to me that I have about 1/2" of front driveshaft slip engaged I moved my front axle forward 1" while going SOA and I guess I've run out of shaft.

Got a few bugs to work out

[DsrtJeeper]

Matt; you may want to look into a new high angle driveline. The 1310 can be clearanced a bit, but would have to be rebalanced I would guess.

Your front shaft can easily be lengthened for about $150.00.

Blaine; you're absolutely correct. (You already knew that.)

[mrblaine]

Originally posted by DsrtJeeper
Matt; you may want to look into a new high angle driveline. The 1310 can be clearanced a bit, but would have to be rebalanced I would guess.

Your front shaft can easily be lengthened for about $150.00.

Blaine; you're absolutely correct. (You already knew that.)

I have my rear axle limit strapped to save the double cardan joint. I have a HP rear, a 19.5" rear driveshaft (that's long considering how high the pinion is) and would like to take advantage of more droop. Thus the call to TW only to get instantly shut down.

My next option is the JBC Super short rear driveshaft. I did consider trying to adapt a 42 degree angle Longfield Birfield into a driveshaft, but can't get it straight in my head yet.

[DsrtJeeper]

Originally posted by mrblaine
I have my rear axle limit strapped to save the double cardan joint. I have a HP rear, a 19.5" rear driveshaft (that's long considering how high the pinion is) and would like to take advantage of more droop. Thus the call to TW only to get instantly shut down.

My next option is the JBC Super short rear driveshaft. I did consider trying to adapt a 42 degree angle Longfield Birfield into a driveshaft, but can't get it straight in my head yet.

That is a long driveshaft for high pinion. Is this due to your flat skid raising the TC higher? I installed a JB super short SYE for a friend, It is a very quality piece. The only downfall is buying the electronic box to calibrate the speedo.

I'm curious... did you run three limiting straps in the rear or just one at each shock? I'm not quite sure what Troy is doing to his cv's, but at full droop my driveshaft does not bind enough to say so.

By the way; what did you do to get your gas tank so flush? I just noticed the flat skid underneath it.

[mrblaine]

Originally posted by DsrtJeeper
That is a long driveshaft for high pinion. Is this due to your flat skid raising the TC higher? I installed a JB super short SYE for a friend, It is a very quality piece. The only downfall is buying the electronic box to calibrate the speedo.

I'm curious... did you run three limiting straps in the rear or just one at each shock? I'm not quite sure what Troy is doing to his cv's, but at full droop my driveshaft does not bind enough to say so.

By the way; what did you do to get your gas tank so flush? I just noticed the flat skid underneath it.

Why would you run 3 straps? One in the middle or one at each shock, in my case, it's shocks.

I don't think Troy can do much to the CV's if they are 1310's and Spicer parts. Least ways not where it does any good.

Gas tank. Made a new one out of aluminum, shoved it up through a hole in the floor, skidded it and used all the stock parts for emissions, return and pump.

[DsrtJeeper]

Originally posted by mrblaine
Why would you run 3 straps? One in the middle or one at each shock, in my case, it's shocks.

I don't think Troy can do much to the CV's if they are 1310's and Spicer parts. Least ways not where it does any good.

Gas tank. Made a new one out of aluminum, shoved it up through a hole in the floor, skidded it and used all the stock parts for emissions, return and pump.

Well; i'm scratching my head ever since I saw three straps on a buggy a few months back. I really don't know.

I have been told by several buggy guys that they prefer one strap in the middle. They claim that it forces the axle to articulate one way or the other when the strap tightens.

My question to you... If I place one centered strap, how does this limit shock travel in the rear when the axle articulates?

[DsrtJeeper]

Am I picturing this wrong??? It seems if you had a center limiting strap; your shocks would be the limiting factor when articulating.

[mrblaine]

Originally posted by DsrtJeeper
Am I picturing this wrong??? It seems if you had a center limiting strap; your shocks would be the limiting factor when articulating.

They would be. If the shocks can handle it and mine can, why not?

Now that I think about it, I may build a truss to hang a pair of center straps from. That would stop the bind at the CV and still let me have more articulation if I wanted it.

Just so the pair doesn't confuse you, I typically run about 50-60 mph back to camp from the outer trails and some of the whoops will launch me off the ground. The pair is to handle the weight of the axle when that happens.

[DsrtJeeper]

Originally posted by mrblaine
They would be. If the shocks can handle it and mine can, why not?

Now that I think about it, I may build a truss to hang a pair of center straps from. That would stop the bind at the CV and still let me have more articulation if I wanted it.

Just so the pair doesn't confuse you, I typically run about 50-60 mph back to camp from the outer trails and some of the whoops will launch me off the ground. The pair is to handle the weight of the axle when that happens.

Bingo!!! I take it the Fox shocks have internal bump stops?

[Matt Pascoe]

I just checked my rear shaft and it binds at 30*. At full axle droop its at 40*. I cant think of any reason that I would ever want my axle drooped that much so I'll probably add a center limit strap at 30*.

I can see that where the 1310 CV is binding there is plenty of beef to do a little clearancing. I'll talk to TW Monday and see what he recomends.

[Matt Pascoe]

Well I just ramped it and flexed the rear out as far as I would ever want it to flex and the rear shaft is operating at 20* and my pinion is still pointed straight at the CV.

Now I'm thinking I'll add a limiting strap at ~25*, leave the CV alone and call it good

[mrblaine]

Originally posted by Matt Pascoe
I just checked my rear shaft and it binds at 30*. At full axle droop its at 40*. I cant think of any reason that I would ever want my axle drooped that much so I'll probably add a center limit strap at 30*.

I can see that where the 1310 CV is binding there is plenty of beef to do a little clearancing. I'll talk to TW Monday and see what he recomends.

It looks like there is beef until you get to the centering ball mechanism. Then you run out of beef quickly.

[Milan]

DsrtJeeper, I like it very much. I'd like to build (or have it built) something similar. Only I was going to triangulate the lowers much more towards the center of the crossmember to have very little rear steer. I think this is why you still notice it at full articualtion but I also think you can't completely get away from it unless a single mounting point where the arms meet is used.

I also thought that if I mount them more in the center, the arms might protect the driveshaft from rocks and stumps a bit that way. Do you really think the crossmember would buckle/bend? I was going to use 3/16" wall 2x4 square tubing laid flat.

MrBlaine/anyone what do you think? Would it be strong enough? Would the lower arms be in a way of obstacles too much (I actually thought I would run them horizontal to about where the front of the rear tires are and then bend them down toward the axle mounts) but I think straight tubes would be stronger and definitely easier to build.

[Milan]

Were my questions stupid?

[mrblaine]

Originally posted by Milan
Were my questions stupid?

Not in the slightest. When I cruise through the sections, I look for the highlited topics that indicate a new reply to a post.

That one didn't show up for some reason, nor did I get an email notification that there had been a reply to a thread I was watching.

Yes, I think 2 x 4 x .188 wall will be strong enough. I don't know about swinging the lowers in towards the pumpkin or how that will affect clearance.

No experience there.

I like mine out where the tires are. Since they are only a small distance in front of the tires at the frame mounts, I have little difficulty getting the tire up on something the arm is dragging on.

[Milan]

Originally posted by mrblaine
Not in the slightest. When I cruise through the sections, I look for the highlited topics that indicate a new reply to a post.

Good. I was worried I killed a good thread. I hate it when that happens.

Originally posted by mrblaine

I like mine out where the tires are. Since they are only a small distance in front of the tires at the frame mounts, I have little difficulty getting the tire up on something the arm is dragging on.

This is my biggest dilema. I think it would be easier to hang the arms off of frame brackets and go straight back, getting the benefit of arms close to the tire and not dragging/hanging up much. The thing I like about the double triangulation would be less stress on the triangulated uppers to keep the axle located side to side and not as much rear steer. I even considered asking TBT to make me some arms so that when they get dragging a lot they could flex a little allowing forward movement as Stu discribed a while ago. I figured you guys watching all kinds of competition rigs might have seen pros and cons of the double tirangulation in person. Bending the arms to keep them away would probably work but I think it's a lot of effort to get the bends in the right spot and angle and then what happens when you stand the jeep on its rear axle? It might tuck in and bend the arms more. I dunno...just thinking out loud.

[mrblaine]

Originally posted by Milan
Good. I was worried I killed a good thread. I hate it when that happens.



This is my biggest dilema. I think it would be easier to hang the arms off of frame brackets and go straight back, getting the benefit of arms close to the tire and not dragging/hanging up much. The thing I like about the double triangulation would be less stress on the triangulated uppers to keep the axle located side to side and not as much rear steer. I even considered asking TBT to make me some arms so that when they get dragging a lot they could flex a little allowing forward movement as Stu discribed a while ago. I figured you guys watching all kinds of competition rigs might have seen pros and cons of the double tirangulation in person. Bending the arms to keep them away would probably work but I think it's a lot of effort to get the bends in the right spot and angle and then what happens when you stand the jeep on its rear axle? It might tuck in and bend the arms more. I dunno...just thinking out loud.

Why are you worried about the uppers? Do you know of any that have failed?

Mine are 1.250 x .120 wall chromolly with 3/4 x 3/4 rod ends and have zero issues. No bending, no worn out rod ends, nothing.

If I did have an issue, it's an easy matter to up the size to 3/4 x 7/8's shank and go to 1.375 uppers and sleeve the .120 wall with 1.125" tubing of any wall thickness I can find.

As for me, I'm gonna leave well enough alone for now, it doesn't seem to have many issues and has proven to be very durable.

[Milan]

Originally posted by mrblaine
Why are you worried about the uppers? Do you know of any that have failed?

Mine are 1.250 x .120 wall chromolly with 3/4 x 3/4 rod ends and have zero issues. No bending, no worn out rod ends, nothing.

If I did have an issue, it's an easy matter to up the size to 3/4 x 7/8's shank and go to 1.375 uppers and sleeve the .120 wall with 1.125" tubing of any wall thickness I can find.

As for me, I'm gonna leave well enough alone for now, it doesn't seem to have many issues and has proven to be very durable.

I have not seen any fail. I just thought it might be easier with double triangulation. But that's not the main reason I'd do it. And of course leaving well enough alone is always hard to argue with.

[Milan]

Oh yeah. What about them bends in the arms and/or TBT alumiflex stuff? Or would you guys stick with Chro-Mo?

[mrblaine]

Originally posted by Milan
Oh yeah. What about them bends in the arms and/or TBT alumiflex stuff? Or would you guys stick with Chro-Mo?

Bends in the arms sound great until you lay under there and figure out that when the axle stuffs, the arm will run into the frame.

Inboard or outboard the mounts and then you have to deal with gravity flopping the arm over to one side or the other. Solve those issues and clearance is a good thing.

Straight arms, I'd do Chromolly. Bent arms I'd go with heavy wall DOM for the cost factor over C/M.

[Darrell C]

I've been doing some research about double triangulated setup also, since I'm considering it. And putting a slight arch in my lower arms.

In addition to factors Blaine mentioned about bending the lower arms, I read a post on POR about someone who put a "decent" bend in the arms and ran into clearance issues with the lowers hitting the uppers. He ended up manufacturing new lowers without a bend to resolve the clearance issue. I would think a slight bend (whatever that is) would improve approach angle to the rear axle without causing too many untoward effects.

[Matt Pascoe]

Re: roll axis and rear steer

I just found this post and it does a good job of explaining how your roll axis effects rear steer.

Double triangulation helps to get a flat roll axis. I think that is the main reason why so many go that route.

My roll axis is a positive 4* (roll over steer) which explains why I have slight rear steer. If I had triangulated the uppers more I could have achieved a flat roll axis.

Raising the upper or lower rear axle mounts also would flatten my roll axis, but would give me more squat at the same time.

[Milan]

Originally posted by mrblaine
Bends in the arms sound great until you lay under there and figure out that when the axle stuffs, the arm will run into the frame.

Inboard or outboard the mounts and then you have to deal with gravity flopping the arm over to one side or the other. Solve those issues and clearance is a good thing.

Straight arms, I'd do Chromolly. Bent arms I'd go with heavy wall DOM for the cost factor over C/M.

Clearance issue duly noted. I figured I'd play it by taking the easiest way out. I.e. if bend causes more issues than it's worth, straight arms it is. I did not think they'd hit the frame though as they'd all be relatively "inside" the framerails.